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Plate Tectonics
Chapter 4
Term | Definition |
---|---|
Crust | the thin and solid outer most layer of the earth above the mantle |
Mantle | the layer of rock between the Earth's crust and core |
Core | the central part of the Earth below the mantle |
lithosphere | the solid, outer layer of the Earth that consists of the crust and rigid upper part of the mantle |
asthenosphere | the soft layer of the mantle on which the tectonic plates move |
mesosphere | the strong, lower part of the mantle between the asthenosphere and the outer core |
tectonic plate | a block of lithosphere that consists of the crust and the rigid, outermost part of the mantle |
continental drift | the hypothesis that the continents once formed a single landmass, broke up, and drifted to their present locations |
sea-floor spreading | the process by which new oceanic lithosphere forms as magma rises toward the surface and solidifies |
plate tectonics | the theory that explains how large pieces of the Earth's outermost layer, called tectonic plates, move and change shape |
convergent boundary | the boundary formed by the collision of two tectonic plates |
divergent boundary | the boundary between two tectonic plates that are moving away from each other |
transform boundary | the boundary between tectonic plates that are sliding past each other horizontally |
compression | stress that occurs when forces act to squeeze an object |
tension | stress that occurs when forces act to stretch an object |
folding | the bending of rock layers due to stress |
fault | a break in a body of rock along which one block slides relative to another |